Interventions to reduce contaminated aerosols produced during dental procedures for preventing infectious diseases.

BACKGROUND: Many dental procedures produce aerosols (droplets, droplet nuclei and splatter) that harbour various pathogenic micro-organisms and may pose a risk for the spread of infections between dentist and patient. The COVID-19 pandemic has led to greater concern about this risk. OBJECTIVES: To assess the effectiveness of methods used during dental treatment procedures to minimize aerosol production and reduce or neutralize contamination in aerosols. SEARCH METHODS: Cochrane Oral Health's Information Specialist searched the following databases on 17 September 2020: Cochrane Oral Health's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (in the Cochrane Library, 2020, Issue 8), MEDLINE Ovid (from 1946); Embase Ovid (from 1980); the WHO COVID-19 Global literature on coronavirus disease; the US National Institutes of Health Trials Registry (ClinicalTrials.gov); and the Cochrane COVID-19 Study Register. We placed no restrictions on the language or date of publication. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on aerosol-generating procedures (AGPs) performed by dental healthcare providers that evaluated methods to reduce contaminated aerosols in dental clinics (excluding preprocedural mouthrinses). The primary outcomes were incidence of infection in dental staff or patients, and reduction in volume and level of contaminated aerosols in the operative environment. The secondary outcomes were cost, accessibility and feasibility. DATA COLLECTION AND ANALYSIS: Two review authors screened search results, extracted data from the included studies, assessed the risk of bias in the studies, and judged the certainty of the available evidence. We used mean differences (MDs) and 95% confidence intervals (CIs) as the effect estimate for continuous outcomes, and random-effects meta-analysis to combine data. We assessed heterogeneity. MAIN RESULTS: We included 16 studies with 425 participants aged 5 to 69 years. Eight studies had high risk of bias; eight had unclear risk of bias. No studies measured infection. All studies measured bacterial contamination using the surrogate outcome of colony-forming units (CFU). Two studies measured contamination per volume of air sampled at different distances from the patient's mouth, and 14 studies sampled particles on agar plates at specific distances from the patient's mouth. The results presented below should be interpreted with caution as the evidence is very low certainty due to heterogeneity, risk of bias, small sample sizes and wide confidence intervals. Moreover, we do not know the 'minimal clinically important difference' in CFU. High-volume evacuator Use of a high-volume evacuator (HVE) may reduce bacterial contamination in aerosols less than one foot (~ 30 cm) from a patient's mouth (MD -47.41, 95% CI -92.76 to -2.06; 3 RCTs, 122 participants (two studies had split-mouth design); very high heterogeneity I² = 95%), but not at longer distances (MD -1.00, -2.56 to 0.56; 1 RCT, 80 participants). One split-mouth RCT (six participants) found that HVE may not be more effective than conventional dental suction (saliva ejector or low-volume evacuator) at 40 cm (MD CFU -2.30, 95% CI -5.32 to 0.72) or 150 cm (MD -2.20, 95% CI -14.01 to 9.61). Dental isolation combination system One RCT (50 participants) found that there may be no difference in CFU between a combination system (Isolite) and a saliva ejector (low-volume evacuator) during AGPs (MD -0.31, 95% CI -0.82 to 0.20) or after AGPs (MD -0.35, -0.99 to 0.29). However, an 'n of 1' design study showed that the combination system may reduce CFU compared with rubber dam plus HVE (MD -125.20, 95% CI -174.02 to -76.38) or HVE (MD -109.30, 95% CI -153.01 to -65.59). Rubber dam One split-mouth RCT (10 participants) receiving dental treatment, found that there may be a reduction in CFU with rubber dam at one-metre (MD -16.20, 95% CI -19.36 to -13.04) and two-metre distance (MD -11.70, 95% CI -15.82 to -7.58). One RCT of 47 dental students found use of rubber dam may make no difference in CFU at the forehead (MD 0.98, 95% CI -0.73 to 2.70) and occipital region of the operator (MD 0.77, 95% CI -0.46 to 2.00). One split-mouth RCT (21 participants) found that rubber dam plus HVE may reduce CFU more than cotton roll plus HVE on the patient's chest (MD -251.00, 95% CI -267.95 to -234.05) and dental unit light (MD -12.70, 95% CI -12.85 to -12.55). Air cleaning systems One split-mouth CCT (two participants) used a local stand-alone air cleaning system (ACS), which may reduce aerosol contamination during cavity preparation (MD -66.70 CFU, 95% CI -120.15 to -13.25 per cubic metre) or ultrasonic scaling (MD -32.40, 95% CI - 51.55 to -13.25). Another CCT (50 participants) found that laminar flow in the dental clinic combined with a HEPA filter may reduce contamination approximately 76 cm from the floor (MD -483.56 CFU, 95% CI -550.02 to -417.10 per cubic feet per minute per patient) and 20 cm to 30 cm from the patient's mouth (MD -319.14 CFU, 95% CI - 385.60 to -252.68). Disinfectants ‒ antimicrobial coolants Two RCTs evaluated use of antimicrobial coolants during ultrasonic scaling. Compared with distilled water, coolant containing chlorhexidine (CHX), cinnamon extract coolant or povidone iodine may reduce CFU: CHX (MD -124.00, 95% CI -135.78 to -112.22; 20 participants), povidone iodine (MD -656.45, 95% CI -672.74 to -640.16; 40 participants), cinnamon (MD -644.55, 95% CI -668.70 to -620.40; 40 participants). CHX coolant may reduce CFU more than povidone iodine (MD -59.30, 95% CI -64.16 to -54.44; 20 participants), but not more than cinnamon extract (MD -11.90, 95% CI -35.88 to 12.08; 40 participants). AUTHORS' CONCLUSIONS: We found no studies that evaluated disease transmission via aerosols in a dental setting; and no evidence about viral contamination in aerosols. All of the included studies measured bacterial contamination using colony-forming units. There appeared to be some benefit from the interventions evaluated but the available evidence is very low certainty so we are unable to draw reliable conclusions. We did not find any studies on methods such as ventilation, ionization, ozonisation, UV light and fogging. Studies are needed that measure contamination in aerosols, size distribution of aerosols and infection transmission risk for respiratory diseases such as COVID-19 in dental patients and staff.

Assessing the efficacy and cost of detergents used in a primary care automated washer disinfector.

Background: Cleaning of re-usable medical devices is a critical control point in the decontamination cycle, although defined end-points of the process are controversial. Objective: Investigate cleaning efficacy and cost of different detergent classes in an automated washer disinfector (AWD) designed for dental practice. Methods: Loads comprised test soiled dental hand instruments in cassettes and extraction forceps. Residual protein assayed using the International standard method (ISO 15883-5:2005) 1% SDS elution with ortho-phthalaldehyde (OPA) or GBox technology (on instrument OPA analysis). Short (60 minutes) and long (97 minutes) AWD cycles were used with four different classes of detergents, tap water and reverse osmosis water. Results: SDS elution analysis (N = 612 instruments) demonstrated four detergents with both wash cycles achieved equivalent cleanliness levels and below a threshold of 200 µg protein/instrument. GBox methodology (N = 575) using UK Department of Health threshold of 5 µg/instrument side demonstrated that tap water performed with the greatest efficacy for all types of instruments and cycle types. Conclusions: Using International standard methodology, different detergent classes had equivalence in cleaning efficacy. Cheaper detergents used in this study performed with similar efficacy to more expensive solutions. Findings emphasise the importance of validating the detergent (type and concentration) for each AWD.

Decontamination technology assessments - who assesses the assessments?

The driver to improve surgical instrument decontamination has been the introduction of vCJD into the UK population over the last two decades, although concerns over transmission of other infectious agents remain valid. Though significant improvements have been made in primary care, this is usually in spite of limited access to technical advice on decontamination equipment. A technology assessment for key elements of equipment and processes used in this environment should be welcomed. However, two reports by the Scottish Health Technology Assessment Panel are flawed in estimating costs associated with wrapping instruments, omission of appropriate references and inaccurate data in the costing models. These assessments contribute little to health economics debates, confuse practitioners and frustrate technical experts.

Massachusetts dental public health program directors practice behaviors and perceptions of infection control.

PURPOSE: The objective of this exploratory study was to deter mine the current infection control practices used in Massachusetts dental public health programs and assess the perceived compliance and challenges with infection control standards as outlined in the 2003 Centers for Disease Control and Prevention (CDC) infection control guidelines. METHODS: A convenience sample of program directors of dental public health programs in Massachusetts (n=82) were invited to participate. The directors were identified through the Massachusetts Department of Public Health, Massachusetts League of Community Health Centers, local dental/dental hygiene schools and key stakeholders in dental public health. The electronic questionnaire-based survey consisted of 26 open/closed-ended and Likert scale questions. Statistical analysis included frequency distribution and factor analysis. RESULTS: The overall response rate was 43%. The majority of responders to the survey were from public health settings using fixed/mobile dental equipment (82.9%), compared to settings using portable equipment (17.1%). Perceived lapses in the guidelines were attributed to lack of finances (r=0.938), lack of personnel (r=0.874) and lack of space (r=0.763). The only significant correlation between the program directors perceived adherence to the CDC guidelines was having access to necessary supplies and equipment (r=0.914). Program directors indicated that the CDC guidelines are hard to apply (r=0.895) and guide lines specific to settings using portable equipment would be helpful (r=0.925). CONCLUSION: Within the limitations of the sample size and response rate, directors from public health settings using both fixed/mobile and portable equipment reported being able to apply the current 2003 CDC infection control guidelines with few compliance challenges. However, respondents indicated that the guidelines were hard to apply and that infection control guidelines for settings using portable equipment would be useful.

Evidence summary: what 'cost of illness' evidence is there about cross-infection related infections in dental practice?

Since August 2009, members of the Primary Care Dentistry Research Forum (http://www.dentistryresearch.org) have taken part in an online vote to identify questions in day-to-day practice that they felt most needed to be answered with conclusive research. The question which receives the most votes each month forms the subject of a critical appraisal of the relevant literature. Each month a new round of voting takes place to decide which further questions will be reviewed. Dental practitioners and dental care professionals are encouraged to take part in the voting and submit their own questions to be included in the vote by joining the website.The paper below details a summary of the findings of the seventh critical appraisal. In conclusion, the critical appraisal identified no evidence on the epidemiological scale of cross-infection caused in dental practices and therefore also of the cost impact of cross-infection caused in primary dental practices. As a result, no 'cost of illness', or cost-benefit assessment, exists or is feasible at this time.

Cost analysis of hand hygiene using antimicrobial soap and water versus an alcohol-based hand rub.

Proper hand hygiene is acknowledged as the most critical element of an adequate infection control program in the oral healthcare setting. However, adherence to proper hand hygiene protocols is often lacking. Poor compliance with hand hygiene protocols has been attributed to such factors as lack of time, hand irritation, hand dryness, forgetfulness, skepticism over importance, understaffing, perceived low risk of cross-infection, inconvenience, and the belief gloves alone offer protection. In the medical environment the use of alcohol-based hand rubs now represent the preferred method of performing hand hygiene when delivering non-surgical care. In this study we compared the costs associated with traditional hand washing against an alcohol-based hand rub protocol in the dental setting. The results indicate an alcohol-based hand rub protocol is less costly and less time consuming when compared to traditional handwashing in the dental setting, creating a new paradigm for hand hygiene in the dental office.

Low-cost screening for microbial contaminants in aerosols generated in a dental office.

It has been reported that aerosols and droplets generated by high-speed dental drills and cavitrons are contaminated with blood and bacteria and represent a potential route for transmitting disease. Bacterial cells possess a negative electrical charge, while the cathode ray tubes (CRT) that are used in computer monitors generate positively charged static electric fields. Consequently, bacteria dispersed within these aerosols could be attracted to the screens on CRT monitors. In this study, pathogenic strains of Staphylococcus aureus were found on CRT screens in different locations within the Louisiana State University School of Dentistry facility. The results suggest that surveying CRT screens is a simple method for evaluating the airborne microbial contaminants present within a dental office.

Disinfection/sterilization in U.S. dental practices--practice behavior and attitudes.

In an era when we are experiencing an increased awareness of communicable infectious diseases such as tuberculosis and hepatitis B, and in which stories regarding the fear of the spread of the HIV virus receive almost nightly news coverage, all health care professionals are taking extra precautions when providing care to patients. The concern of occupational transmission of infectious diseases from the perspective of patient to health care worker is not new. However, the sensationalized singular instance of a dentist in Florida who reportedly transmitted the HIV virus to five of his patients raises questions about the possibility of health care worker to patient transmission and puts the spotlight on the dental community.

Today's minimal requirements for a practical dental office infection control and exposure control program.

The current climate in society regarding infectious diseases in general, and herpes, hepatitis, and HIV infections in particular, dictates that today's dental practices must use effective infection control techniques. The Occupational Safety and Health Administration continues to inspect, cite, and fine health care facilities. More states are implementing regulations concerning the operation of health care facilities. Patients are becoming more sophisticated in their scrutinizing of the dental and medical professions' approach to asepsis. Media coverage of exposure incidents is becoming more intense. All these factors leave dentists no choice; they must implement appropriate infection control techniques. The life-time cost of effective infection control is far less than one malpractice settlement. Implementation of an effective infection control program to promote dental asepsis can be cost-effective. In addition, it can be a practice builder.

HIV and the dental profession.

In order to assess the response of dentists to the increasing incidence of HIV, a study was conducted to explore their attitudes, knowledge and the additional costs involved in treating HIV positive patients. The response of dentists to the increasing incidence of HIV positive patients is influenced by their fears and concerns about HIV, their knowledge about the disease, and their attitudes towards providing care for HIV patients. The results of this research suggest that the negative response to HIV patients from dentists can be attributed to several factors. Dentists are afraid of contracting the virus, they do not trust the honesty of HIV patients, and they believe there are additional costs involved in treating these patients. In order to provide quality dental treatment for HIV patients, dentists must overcome their misperceptions and feelings of anxiety and fear about HIV. Education is a major weapon in the fight against HIV. Dentists agree there is a need for continuing education despite the fact that their overall knowledge about HIV is good.

Infection control.

Sterility. Infection control. Patient protection. It's all the same thing. It's required and it's costly. However, we need to turn it into a positive aspect of our practices. The old marketing axiom still applies-you have to market your marketing! Stop viewing patient protection as just one more overhead expense and begin to use it as a benefit that can help prove how committed to your patients you are.